Agreed that sugar, and so NDLG (liver made fat) is probably the most common cause, but the liver needs choline to export it.

There's plenty of evidence that a choline-deficient diet can lead to NAFL.

Nutritionist Chris Masterjohn has kindly put up a database of the content of choline in various foods. This info is available elsewhere online, but it scattered across papers and publications - and this makes it easy.

That said, our best source of choline? Eggs.

BTW/FWIW, I'm aware of choline as I'm a sub-par methylator (AKA MTHFR) and my biology is using up choline (plus betaine, and some others) as a methyl donor - so I need to pay attention to choline.

Disclaimer: not a bio guy, just motivated by self-interest, picking up some organic chem as I go. This might all be nonsense - do your own research.